In smaller sized greenhouses, a manual system opened and closed by hand could possibly be installed. These work simplest when the screen materials is supported by a track system.
Start time – when in the morning will the display screen system start operation
Stop time – when in the afternoon will the display screen system stop operation
Light level – in what light strength will the screen end up being activated either to open or close
Maximum/minimum temperature 
– what are the limitations of temperature desired
Maximum/minimum humidity – What exactly are the limitations of humidity desired
Gap positions – this sets the percent open or close placement under different circumstances such as early on a winter early morning to reduce thermal shock or through the summer to supply better shading. The gap actions and speed of movement can be controlled in some systems.
Time delay – under changeable climate this avoids frequent opening and closing
Wind speed – To reduce warmth loss, the screen could be closed early under high wind speed conditions
Snow detection – this can open the display and turn on the heat when it begins to snow.
The standard system uses nylon monofilament or stainless cables to support the screen materials. The screen material can possibly rest on top of the network of cables or become suspended by hooks from the cables. A gearmotor powers a drum or rack and pinion that movements the leading edge of the screen material. Control can be either with a manual change or electronic controller.
Based on the above, the grower must enter the following parameters into the controller:
A weather station is required to provide outdoor light level, temperature, humidity, wind and rain or snow rack drive for greenhouse china conditions.